Vehicle belly pan

ABSTRACT

A vehicle chassis having substantially all of the mechanical, electrical, and structural componentry necessary for a fully functional vehicle includes at least an energy conversion system, a steering system, and a braking system. The chassis is configured for matability with a variety of different types or styles of vehicle bodies. Various prior art mechanical control linkages between a driver and controlled systems are replaced with non-mechanical control signal transmission components. Fuel cell technology is also implemented. A quick plastic formed (QPF) rigid sheet (belly pan) includes cavities formed therein to facilitate attachment of various components of the energy conversion system, energy storage system, braking system, steering system, etc.

REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. ProvisionalApplications 60/337,994, filed Aug. 23, 2001 and Dec. 7, 2001, both ofwhich by incorporated by reference in their entireties.

TECHNICAL FIELD

[0002] This invention relates to a vehicle chassis belly pan which is arigid sheet having cavities formed therein to receive chassiscomponents.

BACKGROUND OF THE INVENTION

[0003] Mobility, being capable of moving from place to place or ofmoving quickly from one state to another, has been one of the ultimategoals of humanity throughout recorded history. The automobile has likelydone more in helping individuals achieve that goal than any otherdevelopment. Since its inception, societies around the globe haveexperienced rates of change in their manner of living that are directlyrelated to the percentage of motor vehicle owners among the population.

[0004] Prior art automobiles and light trucks include a body, thefunction of which is to contain and protect passengers and theirbelongings. Bodies are connected to the numerous mechanical, electrical,and structural components that, in combination with a body, comprise afully functional vehicle. The nature of the prior art connectionsbetween a vehicle body and vehicular componentry may result in certaininefficiencies in the design, manufacture, and use of vehicles. Threecharacteristics of prior art body connections that significantlycontribute to these inefficiencies are the quantity of connections; themechanical nature of many of the connections; and the locations of theconnections on the body and on the componentry.

[0005] In the prior art, the connections between a body and componentryare numerous. Each connection involves at least one assembly step when avehicle is assembled; it is therefore desirable to reduce the number ofconnections to increase assembly efficiency. The connections between aprior art body and prior art vehicular componentry include multipleload-bearing connectors to physically fasten the body to the othercomponents, such as bolts and brackets; electrical connectors totransmit electrical energy to the body from electricity-generatingcomponents and to transmit data from sensors that monitor the status ofthe componentry; mechanical control linkages, such as the steeringcolumn, throttle cable, and transmission selector; and ductwork andhoses to convey fluids such as heated and cooled air from an HVAC unitto the body for the comfort of passengers.

[0006] Many of the connections in the prior art, particularly thoseconnections that transmit control signals, are mechanical linkages. Forexample, to control the direction of the vehicle, a driver sends controlsignals to the steering system via a steering column. Mechanicallinkages result in inefficiencies, in part, because different driverlocations in different vehicles require different mechanical linkagedimensions and packaging. Thus, new or different bodies often cannot use“off-the-shelf” components and linkages. Componentry for one vehiclebody configuration is typically not compatible for use with othervehicle body configurations. Furthermore, if a manufacturer changes thedesign of a body, a change in the design of the mechanical linkage andthe component to which it is attached may be required. The change indesign of the linkages and components requires modifications to thetooling that produces the linkages and components.

[0007] The location of the connections on prior art vehicle bodies andcomponentry also results in inefficiencies. In prior art body-on-framearchitecture, connection locations on the body are often not exposed toan exterior face of the body, and are distant from correspondingconnections on the componentry; therefore, long connectors such aswiring harnesses and cables must be routed throughout the body fromcomponentry. The vehicle body of a fully-assembled prior art vehicle isintertwined with the componentry and the connection devices, renderingseparation of the body from its componentry difficult andlabor-intensive, if not impossible. The use of long connectors increasesthe number of assembly steps required to attach a vehicle to itscomponentry.

[0008] Furthermore, prior art vehicles typically have internalcombustion engines that have a height that is a significant proportionof the overall vehicle height. Prior art vehicle bodies are thereforedesigned with an engine compartment that occupies about a third of thefront (or sometimes the rear) of the body length. Compatibility betweenan engine and a vehicle body requires that the engine fit within thebody's engine compartment without physical part interference. Moreover,compatibility between a prior art chassis with an internal combustionengine and a vehicle body requires that the body have an enginecompartment located such that physical part interference is avoided. Forexample, a vehicle body with an engine compartment in the rear is notcompatible with a chassis with an engine in the front.

SUMMARY OF THE INVENTION

[0009] A self-contained chassis has substantially all of the mechanical,electrical, and structural componentry necessary for a fully functionalvehicle, including at least an energy conversion system, a suspensionand wheels, a steering system, and a braking system. The chassis has asimplified, and preferably standardized, interface with connectioncomponents to which bodies of substantially varying design can beattached. X-by-wire technology may be utilized to eliminate mechanicalcontrol linkages. Fuel cell technology may also be implemented in theenergy conversion system.

[0010] A result is the reduction in the amount of time and resourcesrequired to design and manufacture new vehicle bodies. Body designs needonly conform to the simple attachment interface of the chassis,eliminating the need to redesign or reconfigure expensive components.

[0011] Further, a multitude of body configurations share a commonchassis, enabling economies of scale for major mechanical, electrical,and structural components.

[0012] Connection components, exposed and unobstructed, increasemanufacturing efficiency because attachment of a body to the chassisrequires only engagement of the connection components to respectivecomplementary connection components on a vehicle body.

[0013] Vehicle owners can increase the functionality of their vehiclesat a lower cost than possible with the prior art because a vehicle ownerneed buy only one chassis upon which to mount a multitude of bodystyles.

[0014] A rigid sheet (belly pan) includes cavities formed therein tofacilitate attachment of various components of the energy conversionsystem, energy storage system, braking system, steering system, etc. Therigid sheet is preferably quick plastic formed (QPF).

[0015] A vehicle chassis in accordance with the invention includes: arigid sheet having formations defining a plurality of cavities; at leastthree wheels mounted with respect to the rigid sheet; an energyconversion system operably connected to at least one wheel; an energystorage system operably connected to the energy conversion system; asteering system operably connected to at least one wheel; and a brakingsystem operably connected to at least one wheel. The energy conversionsystem, energy storage system, steering system, and braking system aremounted with respect to the rigid sheet and each is at least partiallylocated within one of the plurality of cavities.

[0016] A method of assembling a vehicle chassis in accordance with theinvention includes mounting an energy conversion system, energy storagesystem, steering system, and braking system to a rigid sheet, whereinthe energy conversion system, energy storage system, steering system,and braking system each include a plurality of operably interconnectedcomponents. The rigid sheet is formed by quick plastic forming (QPF) toinclude a plurality of cavities of predetermined size, location, andshape. The predetermined size, location, and shape of each of theplurality of cavities are determined to position the components withrespect to the rigid sheet and to at least partially contain thecomponents on the rigid sheet.

[0017] The rigid sheet (belly pan) also enables modular chassiscomponents, such as fuel cells and hydrogen storage tanks, to beinterchanged on the rigid sheet over the life of the chassis.

[0018] The above objects, features, and advantages, and other objects,features, and advantages of the present invention are readily apparentfrom the following detailed description of the best mode for carryingout the invention when taken in connection with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a schematic illustration in perspective view of avehicle rolling platform according to an embodiment of the presentinvention;

[0020]FIG. 2 is a top view schematic illustration of the vehicle rollingplatform shown in FIG. 1;

[0021]FIG. 3 is a bottom view schematic illustration of the vehiclerolling platform shown in FIGS. 1 and 2;

[0022]FIG. 4 is a schematic illustration in side view of a vehicle bodypod and rolling platform attachment scenario according to the presentinvention that is useful with the embodiment of FIGS. 1-3;

[0023]FIG. 5 is a schematic illustration of a vehicle body pod androlling platform attachment scenario, wherein body pods of differingconfigurations are each attachable to identical rolling platforms;

[0024]FIG. 6 is a schematic illustration of a steering system for usewith the rolling platform and body pod shown in FIG. 4;

[0025]FIG. 7 is a schematic illustration of an alternative steeringsystem for use in the rolling platform and body pod of FIG. 4;

[0026]FIG. 8 is a schematic illustration of a braking system for usewith the rolling platform and body pod of FIG. 4;

[0027]FIG. 9 is a schematic illustration of an alternative brakingsystem for use with the rolling platform and body pod of FIG. 4;

[0028]FIG. 10 is a schematic illustration of an energy conversion systemfor use with the rolling platform and body pod of FIG. 4;

[0029]FIG. 11 is a schematic illustration of an alternative energyconversion system for use with the rolling platform and body pod of FIG.4;

[0030]FIG. 12 is a schematic illustration of a suspension system for usewith the rolling platform of FIGS. 1-5;

[0031]FIG. 13 is a schematic illustration of an alternative suspensionsystem for use with the rolling platform and body pod of FIG. 4;

[0032]FIG. 14 is a schematic illustration of a chassis computer andchassis sensors for use with the rolling platform and body pod of FIG.4;

[0033]FIG. 15 is a schematic illustration of a master control unit witha suspension system, braking system, steering system, and energyconversion system for use with the rolling platform and body pod of FIG.4;

[0034]FIG. 16 is a perspective illustration of a skinned rollingplatform according to a further embodiment of the present invention;

[0035]FIG. 17 is a perspective illustration of a skinned rollingplatform according to another embodiment of the present invention;

[0036]FIG. 18 is a side schematic illustration of a rolling platformwith an energy conversion system including an internal combustionengine, and gasoline tanks;

[0037]FIG. 19 is a side schematic illustration of a rolling platformaccording to another embodiment of the invention, with a mechanicalsteering linkage and passenger seating attachment couplings;

[0038]FIGS. 20 and 20a show partial exploded perspective schematicillustrations of a rolling platform according to a further embodiment ofthe invention in an attachment scenario with a body pod, the rollingplatform having multiple electrical connectors engageable withcomplementary electrical connectors in the body pod;

[0039]FIG. 21 is a perspective schematic illustration of a skinnedrolling platform according to yet another embodiment of the invention,the rolling platform having a movable control input device;

[0040]FIG. 22 is a schematic perspective view of rigid sheet or bellypan in accordance with the invention;

[0041]FIG. 23 is a schematic perspective illustration of various stepsof a chassis assembly process using the rigid sheet of FIG. 22;

[0042]FIG. 24 is a schematic perspective view of an engineered floorpanin accordance with the invention;

[0043]FIG. 24a is a schematic perspective illustration of various stepsof a body assembly process using the engineered floorpan of FIG. 24;

[0044]FIG. 25 is a schematic perspective illustration of the attachmentof a body to a chassis in accordance with the invention;

[0045]FIG. 26 is a schematic perspective illustration of various stepsof a chassis assembly process in accordance with the invention;

[0046]FIG. 27 is a schematic perspective illustration of various stepsof a body assembly process, and the attachment of the body to thechassis of FIG. 26; and

[0047]FIG. 28 is a flow chart illustrating a method of assembling achassis in accordance with the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0048] Referring to FIG. 1, a vehicle chassis 10 in accordance with theinvention, also referred to as the “rolling platform,” includes astructural frame 11. The structural frame 11 depicted in FIG. 1comprises a series of interconnected structural elements including upperand lower side structural elements 12 and 14 that comprise a“sandwich”-like construction. Elements 12 and 14 are substantially rigidtubular (or optionally solid), members that extend longitudinallybetween the front and rear axle areas 16, 18, and are positionedoutboard relative to similar elements 20, 22. The front and rear ends ofelements 12, 14 are angled inboard, extending toward elements 20 and 22and connecting therewith prior to entering the axle areas 16, 18. Foradded strength and rigidity a number of vertical and angled structuralelements extend between elements 12, 14, 20 and 22. Similar to theelements 12, 14, 20 and 22, which extend along the left side of therolling platform 10, a family of structural elements 26, 28, 30 and 32extend along the right side thereof.

[0049] Lateral structural elements 34, 36 extend between elements 20, 30and 22, 32, respectively nearer the front axle area 16 and lateralstructural elements 38, 40 extend between elements 20, 30 and 22, 32,respectively nearer the rear axle area 18, thereby defining amid-chassis space 41. The front axle area 16 is defined in and aroundstructural elements 43, 44 at the rear and front, and on the sides bystructural elements 46, 48 which may be extensions of the elements 20,22, 30, 32 or connected therewith. Forward of the front axle area, aforward space is defined between element 44 and elements 50, 52. Therear axle area 18 is defined in and around structural elements 53, 54 atthe front and rear, and on the sides by structural elements 56, 58,which may be extensions of the elements 20, 22, 30, 32 or connectedtherewith. Rearward of the rear axle area 18, a rearward space isdefined between element 54 and elements 60, 62. Alternatively, the rearaxle area 18 or the rearward space may be elevated relative to the restof the structural frame 11 if necessary to accommodate an energyconversion system, and the frame may include other elements to surroundand protect an energy conversion system. The frame defines a pluralityof open spaces between the elements described above. Those skilled inthe art will recognize materials and fastening methods suitable for usein the structural frame. For example, the structural elements may betubular, aluminum, and welded at their respective connections to otherstructural elements.

[0050] The structural frame 11 provides a rigid structure to which anenergy conversion system 67, energy storage system 69, suspension system71 with wheels 73, 75, 77, 79 (each wheel having a tire 80), steeringsystem 81, and braking system 83 are mounted, as shown in FIGS. 1-3, andis configured to support an attached body 85, as shown in FIG. 4. Aperson of ordinary skill in the art will recognize that the structuralframe 11 can take many different forms, in addition to the cage-likestructure of the embodiment depicted in FIGS. 1-3. For example, thestructural frame 11 can be a traditional automotive frame having two ormore longitudinal structural members spaced a distance apart from eachother, with two or more transverse structural members spaced apart fromeach other and attached to both longitudinal structural members at theirends. Alternatively, the structural frame may also be in the form of a“belly pan,” wherein integrated rails and cross members are formed insheets of metal or other suitable material, with other formations toaccommodate various system components. The structural frame may also beintegrated with various chassis components.

[0051] Referring to FIG. 2, a body attachment interface 87 is defined asthe sum of all body connection components, i.e., connective elementsthat function to operably mate a vehicle body to the chassis 10. Thebody connection components of the preferred embodiment include aplurality of load-bearing body-retention couplings 89 mounted withrespect to the structural frame 11 and a single electrical connector 91.

[0052] As shown in FIG. 4, the load-bearing body-retention couplings 89are engageable with complementary attachment couplings 93 on a vehiclebody 85 and function to physically fasten the vehicle body 85 to thechassis 10. Those skilled in the art will recognize that a multitude offastening and locking elements may be used and fall within the scope ofthe claimed invention. The load-bearing body-retention couplings 89 arepreferably releasably engageable with complementary couplings, thoughnon-releasably engageable couplings such as weld flanges or rivetingsurfaces may be employed within the scope of the claimed invention.Ancillary fastening elements may be used as lock downs in conjunctionwith the load-bearing body-retention couplings. Load-bearing surfaceswithout locking or fastening features on the chassis 10 may be used withthe load-bearing body-retention couplings 89 to support the weight of anattached vehicle body 85. In the preferred embodiment, the load-bearingbody-retention couplings 89 include support brackets with bolt holes.Rubber mounts (not shown) located on the support brackets dampenvibrations transmitted between the body and the chassis. Alternatively,hard mounts may be employed for body-retention couplings.

[0053] The electrical connector 91 is engageable with a complementaryelectrical connector 95 on a vehicle body 85. The electrical connector91 of the preferred embodiment may perform multiple functions, or selectcombinations thereof. First, the electrical connector 91 may function asan electrical power connector, i.e., it may be configured to transferelectrical energy generated by components on the chassis 10 to a vehiclebody 85 or other non-chassis destination. Second, the electricalconnector 91 may function as a control signal receiver, i.e., a deviceconfigured to transfer non-mechanical control signals from a non-chassissource to controlled systems including the energy conversion system,steering system, and braking system. Third, the electrical connector 91may function as a feedback signal conduit through which feedback signalsare made available to a vehicle driver. Fourth, the electrical connector91 may function as an external programming interface through whichsoftware containing algorithms and data may be transmitted for use bycontrolled systems. Fifth, the electrical connector may function as aninformation conduit through which sensor information and otherinformation is made available to a vehicle driver. The electricalconnector 91 may thus function as a communications and power “umbilical”port through which all communications between the chassis 10 and anattached vehicle body 85 are transmitted. Electrical connectors includedevices configured to operably connect one or more electrical wires withother electrical wires. The wires may be spaced a distance apart toavoid any one wire causing signal interference in another wire operablyconnected to an electrical connector or for any reason that wires inclose proximity may not be desirable.

[0054] If one electrical connector performing multiple functions is notdesirable, for example, if a cumbersome wire bundle is required, orpower transmission results in control signal interference, the bodyattachment interface 87 may include a plurality of electrical connectors91 engageable with a plurality of complementary electrical connectors 95on a vehicle body 85, with different connectors performing differentfunctions. A complementary electrical connector 95 performs functionscomplementary to the function of the electrical connector with which itengages, for example, functioning as a control signal transmitter whenengaged with a control signal receiver.

[0055] Referring again to FIGS. 1-3, the energy conversion system 67,energy storage system 69, steering system 81, and braking system 83, areconfigured and positioned on the chassis 10 to minimize the overallvertical height of the chassis 10 and to maintain a substantiallyhorizontal upper chassis face 96. A face of an object is an imaginarysurface that follows the contours of the object that face, and aredirectly exposed to, a particular direction. Thus, the upper chassisface 96 is an imaginary surface that follows the upwardly facing andexposed contours of the chassis frame 11 and systems mounted therein.Matable vehicle bodies have a corresponding lower body face 97 that isan imaginary surface that follows the downwardly facing and exposedcontours of the body 85, as shown in FIG. 4.

[0056] Referring again to FIGS. 1-3, the structural frame 11 has athickness defined as the vertical distance between its highest point(the top of structural element 20) and its lowest point (the bottom ofstructural element 22). In the preferred embodiment, the structuralframe thickness is approximately 11 inches. To achieve a substantiallyhorizontal upper chassis face 96, the energy conversion system 67,energy storage system 69, steering system 81, and braking system 83 aredistributed throughout the open spaces and are configured, positioned,and mounted to the structural frame 11 such that the highest point ofany of the energy conversion system 67, energy storage system 69,steering system 81, and braking system 83 does not extend or protrudehigher than the highest point of the structural frame 11 by an amountmore than 50% of the structural frame thickness. Alternatively, thehighest point of any of the energy conversion system 67, energy storagesystem 69, steering system 81, and braking system 83 does not extend orprotrude higher than the top of any of the tires 80. Alternatively, thehighest point of any of the energy conversion system 67, energy storagesystem 69, steering system 81, and braking system 83 does not extend orprotrude higher than the top of any of the wheels 73, 75, 77, 79. In thecontext of the present invention, a tire is not considered part of awheel. A wheel typically comprises a rim and a wheel disc or nave thatconnects the rim to a wheel hub, and does not include a mounted tire. Atire is mounted around the periphery of a wheel. The substantiallyhorizontal upper chassis face 96 enables the attached vehicle body 85 tohave a passenger area that extends the length of the chassis, unlikeprior art bodies that have an engine compartment to accommodate avertically-protruding internal combustion engine.

[0057] Most of the powertrain load is evenly distributed between thefront and rear of the chassis so there is a lower center of gravity forthe whole vehicle without sacrificing ground clearance, thereby enablingimproved handling while resisting rollover forces.

[0058] Referring again to FIG. 4, the preferred embodiment of therolling platform 10 is configured such that the lower body face 97 of amatable vehicle body 85 is positioned closely adjacent to the upperchassis face 96 for engagement with the rolling platform 10. The bodyconnection components have a predetermined spatial relationship relativeto one another, and are sufficiently positioned, exposed, andunobstructed such that when a vehicle body 85 having complementaryconnection components (complementary attachment couplings 93 and acomplementary electrical connector 95) in the same predetermined spatialrelationship as the body connection components is sufficientlypositioned relative to the upper chassis face 96 of a chassis 10 of theinvention, the complementary connection components are adjacent tocorresponding body connection components and ready for engagement, asdepicted in FIG. 4. In the context, of the present invention, a bodyconnection component having a protective covering is exposed andunobstructed if the protective covering is removable or retractable.

[0059] Each body connection component has a spatial relationshiprelative to each of the other body connection components that can beexpressed, for example, as a vector quantity. Body connection componentsand complementary connection components have the same predeterminedspatial relationship if the vector quantities that describe the spatialrelationship between a body connection component and the other bodyconnection components to be engaged also describe the spatialrelationship between a corresponding complementary connection componentand the other complementary connection components to be engaged. Forexample, the spatial relationship may be defined as follows: a firstbody connection component is spaced a distance Ax+By from a referencepoint; a second body connection component is spaced a distance Cx+Dyfrom the reference point; a third body connection component is spaced adistance Ex+Fy from the reference point, etc. Correspondingcomplementary connection components in the same predetermined spatialrelationship are spaced in a mirror image relationship in the lower bodyface, as depicted in FIGS. 4 and 5. A protective covering (not shown)may be employed to protect any of the body connection components.

[0060] The body connection components and the complementary connectioncomponents are preferably adjacent without positional modification whena vehicle body 85 is sufficiently positioned relative to a chassis 10 ofthe invention; however, in the context of the present invention, thebody connection components may be movable relative to each other withina predetermined spatial relationship to accommodate build tolerances orother assembly issues. For example, an electrical connector may bepositioned and operably connected to a signal-carrying cable. The cablemay be fixed relative to the structural frame at a point six inches fromthe electrical connector. The electrical connector will thus be movablewithin six inches of the fixed point on the cable. A body connectioncomponent is considered adjacent to a complementary connection componentif one or both are movable within a predetermined spatial relationshipso as to be in contact with each other.

[0061] Referring to FIG. 5, the body-attachment interface of the claimedinvention enables compatibility between the chassis 10 and differenttypes of bodies 85, 85′, 85″ having substantially different designs.Bodies 85, 85′, 85″ having a common base 98 with complementaryattachment couplings 93 and complementary electrical connectors 95 inthe same predetermined spatial relationship with one another as thepredetermined spatial relationship between body connection components onthe body-attachment interface 87, are each matable with the chassis 10by positioning the body 85, 85′, 85″ relative to the chassis 10 suchthat each complementary attachment coupling 93 is adjacent to aload-bearing body-retention coupling 89, and the complementaryelectrical connector 95 is adjacent to the electrical connector 91. Inaccordance with the preferred embodiment of the present invention, allbodies and chassis comply with this common, standardized interfacesystem, thereby enabling a wide array of different body types and stylesto be attached to a single chassis design. The substantially horizontalupper chassis face 96 also facilitates compatibility between the rollingplatform 10 and a multitude of differently-configured body styles. Thecommon base 98 functions as a body structural unit and forms the lowerbody face 97 in the preferred embodiment. FIG. 5 schematically depicts asedan 85, a van 85′, and a pickup truck 85″ each having a common base98.

[0062] The body connection components are preferably sufficientlyexposed at a chassis face to facilitate attachment to complementaryconnection components on a matable vehicle body. Similarly,complementary connection components on a matable vehicle body aresufficiently exposed at a body face to facilitate attachment to bodyconnection components on a vehicle chassis. In the preferred embodimentof the invention, the body connection components are located at or abovethe upper chassis face for engagement with complementary connectioncomponents located at or below a lower body face.

[0063] It is within the scope of the claimed invention to employ aconnection device to engage or operably connect a body connectioncomponent with a distant complementary connection component, in thesituation where a vehicle body does not have complementary connectioncomponents in the same predetermined spatial relationship as the bodyconnection components on a vehicle chassis. For example, a cable havingtwo connectors, one connector engageable with the electrical connectoron a body attachment interface and the other connector engageable with acomplementary connector on a matable vehicle body, may be used tooperably connect the electrical connector and the complementaryconnector.

[0064] The bodies 85, 85′, 85″ shown schematically in FIG. 5 each useall of the body connection components on the vehicle chassis 10.However, within the scope of the claimed invention, a chassis may havemore body connection components than are actually mated with a vehiclebody. For example, a chassis may have ten load-bearing body-retentioncouplings, and be matable with a body that engages only five of the tenload-bearing body-retention couplings. Such an arrangement isparticularly useful when an attachable body is of a different size thanthe chassis. For example, a matable body may be smaller than a chassis.Similarly, and within the scope of the claimed invention, a body may bemodular such that separate body components are independently connectedto the vehicle chassis by the load-bearing body-retention couplings.

[0065] A body may have more complementary connection components than areengageable with the body connection components of a particular chassis.Such an arrangement may be employed to enable a particular body to bematable to multiple chassis each having a different predeterminedspatial relationship among its body connection components.

[0066] The load-bearing body-retention couplings 89 and the electricalconnector 91 are preferably releasably engageable without damage toeither an attached body 85 or the chassis 10, thereby enabling removalof one body 85 from the chassis 10 and installation of a different body85′, 85″ on the chassis 10.

[0067] In the preferred embodiment, the body-attachment interface 87 ischaracterized by the absence of any mechanical controlsignal-transmission linkages and any couplings for attaching mechanicalcontrol signal-transmission linkages. Mechanical control linkages, suchas steering columns, limit the compatibility between a chassis andbodies of different configurations.

[0068] Referring to FIG. 1, the steering system 81 is housed in thefront axle area 16 and is operably connected to the front wheels 73, 75.Preferably, the steering system 81 is responsive to non-mechanicalcontrol signals. In the preferred embodiment, the steering system 81 isby-wire. A by-wire system is characterized by control signaltransmission in electrical form. In the context of the presentinvention, “by-wire” systems, or systems that are controllable“by-wire,” include systems configured to receive control signals inelectronic form via a control signal receiver on the body attachmentinterface 87, and respond in conformity to the electronic controlsignals.

[0069] Referring to FIG. 6, the by-wire steering system 81 of thepreferred embodiment includes a steering control unit 98, and a steeringactuator 99. Sensors 100 are located on the chassis 10 and transmitsensor signals 101 carrying information concerning the state orcondition of the chassis 10 and its component systems. The sensors 100may include position sensors, velocity sensors, acceleration sensors,pressure sensors, force and torque sensors, flow meters, temperaturesensors, etc. The steering control unit 98 receives and processes sensorsignals 101 from the sensors 100 and electrical steering control signals102 from the electrical connector 91, and generates steering actuatorcontrol signals 103 according to a stored algorithm. A control unittypically includes a microprocessor, ROM and RAM and appropriate inputand output circuits of a known type for receiving the various inputsignals and for outputting the various control commands to theactuators. Sensor signals 101 may include yaw rate, lateralacceleration, angular wheel velocity, tie-rod force, steering angle,chassis velocity, etc.

[0070] The steering actuator 99 is operably connected to the frontwheels 73, 75 and configured to adjust the steering angle of the frontwheels 73, 75 in response to the steering actuator control signals 103.Actuators in a by-wire system transform electronic control signals intoa mechanical action or otherwise influence a system's behavior inresponse to the electronic control signals. Examples of actuators thatmay be used in a by-wire system include electromechanical actuators suchas electric servomotors, translational and rotational solenoids,magnetorheological actuators, electrohydraulic actuators, andelectrorheological actuators. Those skilled in the art will recognizeand understand mechanisms by which the steering angle is adjusted. Inthe preferred embodiment, the steering actuator 99 is an electric drivemotor configured to adjust a mechanical steering rack.

[0071] Referring again to FIG. 6, the preferred embodiment of thechassis 10 is configured such that it is steerable by any source ofcompatible electrical steering control signals 102 connected to theelectrical connector 91. FIG. 6 depicts a steering transducer 104located on an attached vehicle body 85 and connected to a complementaryelectrical connector 95. Transducers convert the mechanical controlsignals of a vehicle driver to non-mechanical control signals. When usedwith a by-wire system, transducers convert the mechanical controlsignals to electrical control signals usable by the by-wire system. Avehicle driver inputs control signals in mechanical form by turning awheel, depressing a pedal, pressing a button, or the like. Transducersutilize sensors, typically position and force sensors, to convert themechanical input to an electrical signal. In the preferred embodiment, a+/−20 degree slide mechanism is used for driver input, and an opticalencoder is used to read input rotation.

[0072] The complementary electrical connector 95 is coupled with theelectrical connector 91 of the body attachment interface 87. Thesteering transducer 104 converts vehicle driver-initiated mechanicalsteering control signals 105 to electrical steering control signals 102which are transmitted via the electrical connector 91 to the steeringcontrol unit 98. In the preferred embodiment, the steering control unit98 generates steering feedback signals 106 for use by a vehicle driverand transmits the steering feedback signals 106 through the electricalconnector 91. Some of the sensors 100 monitor linear distance movementof the steering rack and vehicle speed. This information is processed bythe steering control unit 98 according to a stored algorithm to generatethe steering feedback signals 106. A torque control motor operablyconnected to the slide mechanism receives the steering feedback signals106 and is driven in the opposite direction of the driver's mechanicalinput.

[0073] In the context of the present invention, a “by-wire” system maybe an actuator connected directly to an electrical connector in the bodyattachment interface. An alternative by-wire steering system 81′ withinthe scope of the claimed invention is depicted schematically in FIG. 7,wherein like reference numbers refer to like components from FIG. 6. Asteering actuator 99 configured to adjust the steering angle of thefront wheels 73, 75 is connected directly to the electrical connector91. In this embodiment, a steering control unit 98′ and a steeringtransducer 104 may be located in an attached vehicle body 85. Thesteering transducer 104 would transmit electrical steering controlsignals 102 to the steering control unit 98′, and the steering controlunit 98′ would transmit steering actuator control signals 103 to thesteering actuator 99 via the electrical connector 91. Sensors 100positioned on the chassis 10 transmit sensor signals 101 to the steeringcontrol unit 98′ via the electrical connector 91 and the complementaryelectrical connector 95.

[0074] Examples of steer-by-wire systems are described in U.S. Pat. No.6,176,341, issued Jan. 23, 2001 to Delphi Technologies, Inc; U.S. Pat.No. 6,208,923, issued Mar. 27, 2001 to Robert Bosch GmbH; U.S. Pat. No.6,219,604, issued Apr. 17, 2001 to Robert Bosch GmbH; U.S. Pat. No.6,318,494, issued Nov. 20, 2001 to Delphi Technologies, Inc.; U.S. Pat.No. 6,370,460, issued Apr. 9, 2002 to Delphi Technologies, Inc.; andU.S. Pat. No. 6,394,218, issued May 28, 2002 to TRW Fahrwerksysteme GmbH& Co. KG; which are hereby incorporated by reference in theirentireties.

[0075] The steer-by-wire system described in U.S. Pat. No. 6,176,341includes a position sensor for sensing angular position of a road wheel,a hand-operated steering wheel for controlling direction of the roadwheel, a steering wheel sensor for sensing position of the steeringwheel, a steering wheel actuator for actuating the hand-operatedsteering wheel, and a steering control unit for receiving the sensedsteering wheel position and the sensed road wheel position andcalculating actuator control signals, preferably including a road wheelactuator control signal and a steering wheel actuator control signal, asa function of the difference between the sensed road wheel position andthe steering wheel position. The steering control unit commands the roadwheel actuator to provide controlled steering of the road wheel inresponse to the road wheel actuator control signal. The steering controlunit further commands the steering wheel actuator to provide feedbackforce actuation to the hand-operated steering wheel in response to thesteering wheel control signal. The road wheel actuator control signaland steering wheel actuator control signal are preferably scaled tocompensate for difference in gear ratio between the steering wheel andthe road wheel. In addition, the road wheel actuator control signal andsteering wheel actuator control signal may each have a gain set so thatthe road wheel control actuator signal commands greater force actuationto the road wheel than the feedback force applied to the steering wheel.

[0076] The steer-by-wire system described in U.S. Pat. No. 6,176,341preferably implements two position control loops, one for the road wheeland one for the hand wheel. The position feedback from the steeringwheel becomes a position command input for the road wheel control loopand the position feedback from the road wheel becomes a position commandinput for the steering wheel control loop. A road wheel error signal iscalculated as the difference between the road wheel command input(steering wheel position feedback) and the road wheel position.Actuation of the road wheel is commanded in response to the road wheelerror signal to provide controlled steering of the road wheel. Asteering wheel error signal is calculated as the difference between thesteering wheel position command (road wheel position feedback) and thesteering wheel position. The hand-operated steering wheel is actuated inresponse to the steering wheel error signal to provide force feedback tothe hand-operated steering wheel.

[0077] The steering control unit of the '341 system could be configuredas a single processor or multiple processors and may include ageneral-purpose microprocessor-based controller, that may include acommercially available off-the-shelf controller. One example of acontroller is Model No. 87C196CA microcontroller manufactured and madeavailable from Intel Corporation of Delaware. The steering control unitpreferably includes a processor and memory for storing and processingsoftware algorithms, has a clock speed of 16 MHz, two optical encoderinterfaces to read position feedbacks from each of the actuator motors,a pulse width modulation output for each motor driver, and a 5-voltregulator.

[0078] U.S. Pat. No. 6,370,460 describes a steer-by-wire control systemcomprising a road wheel unit and a steering wheel unit that operatetogether to provide steering control for the vehicle operator. Asteering control unit may be employed to support performing the desiredsignal processing. Signals from sensors in the road wheel unit, steeringwheel unit, and vehicle speed are used to calculate road wheel actuatorcontrol signals to control the direction of the vehicle and steeringwheel torque commands to provide tactile feedback to the vehicleoperator. An Ackerman correction may be employed to adjust the left andright road wheel angles correcting for errors in the steering geometryto ensure that the wheels will track about a common turn center.

[0079] Referring again to FIG. 1, a braking system 83 is mounted to thestructural frame 11 and is operably connected to the wheels 73, 75, 77,79. The braking system is configured to be responsive to non-mechanicalcontrol signals. In the preferred embodiment, the braking system 83 isby-wire, as depicted schematically in FIG. 8, wherein like referencenumbers refer to like components from FIGS. 6 and 7. Sensors 100transmit sensor signals 101 carrying information concerning the state orcondition of the chassis 10 and its component systems to a brakingcontrol unit 107. The braking control unit 107 is connected to theelectrical connector 91 and is configured to receive electrical brakingcontrol signals 108 via the electrical connector 91. The braking controlunit 107 processes the sensor signals 101 and the electrical brakingcontrol signals 108 and generates braking actuator control signals 109according to a stored algorithm. The braking control unit 107 thentransmits the braking actuator control signals 109 to braking actuators110, 111, 112, 113 which act to reduce the angular velocity of thewheels 73, 75, 77, 79. Those skilled in the art will recognize themanner in which the braking actuators 110, 111, 112, 113 act on thewheels 73, 75, 77, 79. Typically, actuators cause contact betweenfriction elements, such as pads and disc rotors. Optionally, an electricmotor may function as a braking actuator in a regenerative brakingsystem.

[0080] The braking control unit 107 may also generate braking feedbacksignals 114 for use by a vehicle driver and transmit the brakingfeedback signals 114 through the electrical connector 91. In thepreferred embodiment, the braking actuators 110, 111, 112, 113 applyforce through a caliper to a rotor at each wheel. Some of the sensors100 measure the applied force on each caliper. The braking control unit107 uses this information to ensure synchronous force application toeach rotor.

[0081] Referring again to FIG. 8, the preferred embodiment of thechassis 10 is configured such that the braking system is responsive toany source of compatible electrical braking control signals 108. Abraking transducer 115 may be located on an attached vehicle body 85 andconnected to a complementary electrical connector 95 coupled with theelectrical connector 91. The braking transducer 115 converts vehicledriver-initiated mechanical braking control signals 116 into electricalform and transmits the electrical braking control signals 106 to thebraking control unit via the electrical connector 91. In the preferredembodiment, the braking transducer 115 includes two hand-grip typeassemblies. The braking transducer 115 includes sensors that measureboth the rate of applied pressure and the amount of applied pressure tothe hand-grip assemblies, thereby converting mechanical braking controlsignals 116 to electrical braking control signals 108. The brakingcontrol unit 107 processes both the rate and amount of applied pressureto provide both normal and panic stopping.

[0082] An alternative brake-by-wire system 83′ within the scope of theclaimed invention is depicted in FIG. 9, wherein like reference numbersrefer to like components from FIGS. 6-8. The braking actuators 110, 111,112, 113 and sensors 100 are connected directly to the electricalconnector 91. In this embodiment, a braking control unit 107′ may belocated in an attached vehicle body 85. A braking transducer 115transmits electrical braking control signals 108 to the braking controlunit 107′, and the braking control unit 107′ transmits braking actuatorsignals 109 to the braking actuators 110, 111, 112, 113 via theelectrical connector 91.

[0083] Examples of brake-by-wire systems are described in U.S. Pat. No.5,366,281, issued Nov. 22, 2994 to General Motors Corporation; U.S. Pat.No. 5,823,636, issued Oct. 20, 1998 to General Motors Corporation; U.S.Pat. No. 6,305,758, issued Oct. 23, 2001 to Delphi Technologies, Inc.;and U.S. Pat. No. 6,390,565, issued May 21, 2002 to Delphi Technologies,Inc.; which are hereby incorporated by reference in their entireties.

[0084] The system described in U.S. Pat. No. 5,366,281 includes an inputdevice for receiving mechanical braking control signals, a brakeactuator and a control unit coupled to the input device and the brakeactuator. The control unit receives brake commands, or electricalbraking control signals, from the input device and provides actuatorcommands, or braking actuator control signals, to control current andvoltage to the brake actuator. When a brake command is first receivedfrom the input device, the control unit outputs, for a firstpredetermined time period, a brake torque command to the brake actuatorcommanding maximum current to the actuator. After the firstpredetermined time period, the control unit outputs, for a secondpredetermined time period, a brake torque command to the brake actuatorcommanding voltage to the actuator responsive to the brake command and afirst gain factor. After the second predetermined time period, thecontrol unit outputs the brake torque command to the brake actuatorcommanding current to the actuator responsive to the brake command and asecond gain factor, wherein the first gain factor is greater than thesecond gain factor and wherein brake initialization is responsive to thebrake input.

[0085] U.S. Pat. No. 6,390,565 describes a brake-by-wire system thatprovides the capability of both travel and force sensors in a brakingtransducer connected to a brake apply input member such as a brake pedaland also provides redundancy in sensors by providing the signal from asensor responsive to travel or position of the brake apply input memberto a first control unit and the signal from a sensor responsive to forceapplied to a brake apply input member to a second control unit. Thefirst and second control units are connected by a bi-directionalcommunication link whereby each controller may communicate its receivedone of the sensor signals to the other control unit. In at least one ofthe control units, linearized versions of the signals are combined forthe generation of first and second brake apply command signals forcommunication to braking actuators. If either control unit does notreceive one of the sensor signals from the other, it neverthelessgenerates its braking actuator control signal on the basis of the sensorsignal provided directly to it. In a preferred embodiment of the system,a control unit combines the linearized signals by choosing the largestin magnitude.

[0086] Referring again to FIG. 1, the energy storage system 69 storesenergy that is used to propel the chassis 10. For most applications, thestored energy will be in chemical form. Examples of energy storagesystems 69 include fuel tanks and electric batteries. In the embodimentshown in FIG. 1, the energy storage system 69 includes two-compressedgas cylinder storage tanks 121 (5,000 psi, or 350 bars) mounted withinthe mid-chassis space 41 and configured to store compressed hydrogengas. Employing more than two compressed gas cylinder storage tanks maybe desirable to provide greater hydrogen storage capacity. Instead ofcompressed gas cylinder storage tanks 121, an alternate form of hydrogenstorage may be employed such as metal or chemical hydrides. Hydrogengeneration or reforming may also be used.

[0087] The energy conversion system 67 converts the energy stored by theenergy storage system 69 to mechanical energy that propels the chassis10. In the preferred embodiment, depicted in FIG. 1, the energyconversion system 67 includes a fuel cell stack 125 located in the rearaxle area 18, and an electric traction motor 127 located in the frontaxle area 16. The fuel cell stack 125 produces a continuously availablepower of 94 kilowatts. Fuel cell systems for vehicular use are describedin U.S. Pat. No. 6,195,999, issued Mar. 6, 2001 to General MotorsCorporation; U.S. Pat. No. 6,223,843, issued May 1, 2001 to GeneralMotors Corporation; U.S. Pat. No. 6,321,145, issued Nov. 20, 2001 toDelphi Technologies, Inc.; and U.S. Pat. No. 6,394,207, issued May 28,2002 to General Motors Corporation; which are hereby incorporated byreference in their entireties.

[0088] The fuel cell stack 125 is operably connected to the compressedgas cylinder storage tanks 121 and to the traction motor 127. The fuelcell stack 125 converts chemical energy in the form of hydrogen from thecompressed gas cylinder storage tanks 121 into electrical energy, andthe traction motor 127 converts the electrical energy to mechanicalenergy, and applies the mechanical energy to rotate the front wheels 73,75. Optionally, the fuel cell stack 125 and traction motor 127 areswitched between the front axle area 16 and rear axle area 18.Optionally, the energy conversion system includes an electric battery(not shown) in hybrid combination with the fuel cell to improve chassisacceleration. Other areas provided between the structural elements areuseful for housing other mechanisms and systems for providing thefunctions typical of an automobile as shown in FIGS. 2 and 3. Thoseskilled in the art will recognize other energy conversion systems 67that may be employed within the scope of the present invention.

[0089] The energy conversion system 67 is configured to respond tonon-mechanical control signals. The energy conversion system 67 of thepreferred embodiment is controllable by-wire, as depicted in FIG. 10. Anenergy conversion system control unit 128 is connected to the electricalconnector 91 from which it receives electrical energy conversion systemcontrol signals 129, and sensors 100 from which it receives sensorsignals 101 carrying information about various chassis conditions. Inthe preferred embodiment, the information conveyed by the sensor signals101 to the energy conversion system control unit 128 includes chassisvelocity, electrical current applied, rate of acceleration of thechassis, and motor shaft speed to ensure smooth launches and controlledacceleration. The energy conversion system control unit 128 is connectedto an energy conversion system actuator 130, and transmits energyconversion system actuator control signals 131 to the energy conversionsystem actuator 130 in response to the electrical energy conversionsystem control signals 129 and sensor signals 101 according to a storedalgorithm. The energy conversion system actuator 130 acts on the fuelcell stack 125 or traction motor 127 to adjust energy output. Thoseskilled in the art will recognize the various methods by which theenergy conversion system actuator 130 may adjust the energy output ofthe energy conversion system. For example, a solenoid may alternatelyopen and close a valve that regulates hydrogen flow to the fuel cellstack. Similarly, a compressor that supplies oxygen (from air) to thefuel cell stack may function as an actuator, varying the amount ofoxygen supplied to the fuel cell stack in response to signals from theenergy conversion system control unit.

[0090] An energy conversion system transducer 132 may be located on avehicle body 85 and connected to a complementary electrical connector 95engaged with the electrical connector 91. The energy conversion systemtransducer 132 is configured to convert mechanical energy conversionsystem control signals 133 to electrical energy conversion systemcontrol signals 129.

[0091] In another embodiment of the invention, as shown schematically inFIG. 11, wherein like reference numbers refer to like components fromFIGS. 6-10, wheel motors 135, also known as wheel hub motors, arepositioned at each of the four wheels 73, 75, 77, 79. Optionally, wheelmotors 135 may be provided at only the front wheels 73, 75 or only therear wheels 77, 79. The use of wheel motors 135 reduces the height ofthe chassis 10 compared to the use of traction motors, and therefore maybe desirable for certain uses.

[0092] Referring again to FIG. 2, a conventional heat exchanger 137 andelectric fan system 139, operably connected to the fuel cell stack 125to circulate coolant for waste heat rejection, is carried in an openingthat exists between the rear axle area 18 and the structural elements54, 60. The heat exchanger 137 is set at an inclined angle to reduce itsvertical profile, but to provide adequate heat rejection it also extendsslightly above the top of elements 12, 26 (as seen in FIG. 4). Althoughthe fuel cell stack 125, heat exchanger 137 and electric fan system 139extend above the structural elements, their protrusion into the body podspace is relatively minor when compared to the engine compartmentrequirements of a conventionally designed automobile, especially whenthe chassis height of the preferred embodiment is approximately a mere15 inches (28 centimeters). Optionally, the heat exchanger 137 ispackaged completely within the chassis' structure with airflow routedthrough channels (not shown).

[0093] Referring again to FIG. 1, the suspension system 71 is mounted tothe structural frame 11 and is connected to four wheels 73, 75, 77, 79.Those skilled in the art will understand the operation of a suspensionsystem, and recognize that a multitude of suspension system types may beused within the scope of the claimed invention. The suspension system 71of the preferred embodiment of the invention is electronicallycontrolled, as depicted schematically in FIG. 12.

[0094] Referring to FIG. 12, the behavior of the electronicallycontrolled suspension system 71 in response to any given road input isdetermined by a suspension control unit 141. Sensors 100 located on thechassis 10 monitor various conditions such as vehicle speed, angularwheel velocity, and wheel position relative to the chassis 10. Thesensors 100 transmit the sensor signals 101 to the suspension controlunit 141. The suspension control unit 141 processes the sensor signals101 and generates suspension actuator control signals 142 according to astored algorithm. The suspension control unit 141 transmits thesuspension actuator control signals 142 to four suspension actuators143, 144, 145, 146. Each suspension actuator 143, 144, 145, 146 isoperably connected to a wheel 73, 75, 77, 79 and determines, in whole orin part, the position of the wheel 73, 75, 77, 79 relative to thechassis 10. The suspension actuators of the preferred embodiment arevariable-force, real time, controllable dampers. The suspension system71 of the preferred embodiment is also configured such that chassis rideheight is adjustable. Separate actuators may be used to vary the chassisride height.

[0095] In the preferred embodiment, the suspension control unit 141 isprogrammable and connected to the electrical connector 91 of thebody-attachment interface 87. A vehicle user is thus able to altersuspension system 71 characteristics by reprogramming the suspensioncontrol unit 141 with suspension system software 147 via the electricalconnector 91.

[0096] In the context of the claimed invention,electronically-controlled suspension systems include suspension systemswithout a suspension control unit located on the chassis 10. Referringto FIG. 13, wherein like reference numbers are used to reference likecomponents from FIG. 12, suspension actuators 143, 144, 145, 146 andsuspension sensors 100 are connected directly to the electricalconnector 91. In such an embodiment, a suspension control unit 141′located on an attached vehicle body 85 can process sensor signals 101transmitted through the electrical connector 91, and transmit suspensionactuator control signals 142 to the suspension actuators 143, 144, 145,146 via the electrical connector 91.

[0097] Examples of electronically controlled suspension systems aredescribed in U.S. Pat. No. 5,606,503, issued Feb. 25, 1997 to GeneralMotors Corporation; U.S. Pat. No. 5,609,353, issued Mar. 11, 1997 toFord Motor Company; and U.S. Pat. No. 6,397,134, issued May 28, 2002 toDelphi Technologies, Inc.; which are hereby incorporated by reference intheir entireties.

[0098] U.S. Pat. No. 6,397,134 describes an electronically controlledsuspension system that provides improved suspension control throughsteering crossover events. In particular, the system senses a vehiclelateral acceleration and a vehicle steering angle and stores, for eachdirection of sensed vehicle lateral acceleration, first and second setsof enhanced suspension actuator control signals for the suspensionactuators of the vehicle. Responsive to the sensed vehicle lateralacceleration and sensed vehicle steering angle, the system applies thefirst set of enhanced actuator control signals to the suspensionactuators if the sensed steering angle is in the same direction as thesensed lateral acceleration and alternatively applies the second set ofenhanced actuator control signals to the suspension actuators if thesensed steering angle is in the opposite direction as the sensed lateralacceleration.

[0099] U.S. Pat. No. 5,606,503 describes a suspension control system foruse in a vehicle including a suspended vehicle body, four un-suspendedvehicle wheels, four variable force actuators mounted between thevehicle body and wheels, one of the variable force actuators at eachcomer of the vehicle, and a set of sensors providing sensor signalsindicative of motion of the vehicle body, motion of the vehicle wheels,a vehicle speed and an ambient temperature. The suspension controlsystem comprises a microcomputer control unit including: means forreceiving the sensor signals; means, responsive to the sensor signals,for determining an actuator demand force for each actuator; means,responsive to the vehicle speed, for determining a first signalindicative of a first command maximum; means, responsive to the ambienttemperature, for determining a second signal indicative of a secondcommand maximum; and means for constraining the actuator demand force sothat it is no greater than a lesser of the first and second commandmaximums.

[0100] Electrically conductive wires (not shown) are used in thepreferred embodiment to transfer signals between the chassis 10 and anattached body 85, and between transducers, control units, and actuators.Those skilled in the art will recognize that other non-mechanical meansof sending and receiving signals between a body and a chassis, andbetween transducers, control units, and actuators may be employed andfall within the scope of the claimed invention. Other non-mechanicalmeans of sending and receiving signals include radio waves and fiberoptics.

[0101] The by-wire systems are networked in the preferred embodiment, inpart to reduce the quantity of dedicated wires connected to theelectrical connector 91. A serial communication network is described inU.S. Pat. No. 5,534,848, issued Jul. 9, 1996 to General MotorsCorporation, which is hereby incorporated by reference in its entirety.An example of a networked drive-by-wire system is described in U.S.patent application Publication No. US 2001/0,029,408, Ser. No.09/775,143, which is hereby incorporated by reference in its entirety.Those skilled in the art will recognize various networking devices andprotocols that may be used within the scope of the claimed invention,such as SAE J1850 and CAN (“Controller Area Network”). A TTP (“TimeTriggered Protocol”) network is employed in the preferred embodiment ofthe invention for communications management.

[0102] Some of the information collected by the sensors 100, such aschassis velocity, fuel level, and system temperature and pressure, isuseful to a vehicle driver for operating the chassis and detectingsystem malfunctions. As shown in FIG. 14, the sensors 100 are connectedto the electrical connector 91 through a chassis computer 153. Sensorsignals 101 carrying information are transmitted from the sensors 100 tothe chassis computer 153, which processes the sensor signals 101according to a stored algorithm. The chassis computer 153 transmits thesensor signals 101 to the electrical connector 91 when, according to thestored algorithm, the sensor information is useful to the vehicledriver. For example, a sensor signal 101 carrying temperatureinformation is transmitted to the electrical connector 91 by the chassiscomputer 153 when the operating temperature of the chassis 10 isunacceptably high. A driver-readable information interface 155 may beattached to a complementary electrical connector 95 coupled with theelectrical connector 91 and display the information contained in thesensor signals 101. Driver-readable information interfaces include, butare not limited to, gauges, meters, LED displays, and LCD displays. Thechassis may also contain communications systems, such as antennas andtelematics systems, that are operably connected to an electricalconnector in the body-attachment interface and configured to transmitinformation to an attached vehicle body.

[0103] One control unit may serve multiple functions. For example, asshown in FIG. 15, a master control unit 159 functions as the steeringcontrol unit, braking control unit, suspension control unit, and energyconversion system control unit.

[0104] Referring again to FIG. 15, the energy conversion system 67 isconfigured to transmit electrical energy 160 to the electrical connector91 to provide electric power for systems located on an attached vehiclebody, such as power windows, power locks, entertainment systems,heating, ventilating, and air conditioning systems, etc. Optionally, ifthe energy storage system 69 includes a battery, then the battery may beconnected to the electrical connector 91. In the preferred embodiment,the energy conversion system 67 includes a fuel cell stack thatgenerates electrical energy and is connected to the electrical connector91.

[0105]FIG. 16 shows a chassis 10 with rigid covering, or “skin,” 161 andan electrical connector or coupling 91 that functions as an umbilicalport. The rigid covering 161 may be configured to function as a vehiclefloor, which is useful if an attached vehicle body 85 does not have alower surface. In FIG. 17 a similarly equipped chassis 10 is shown withan optional vertical fuel cell stack 125. The vertical fuel cell stack125 protrudes significantly into the body pod space which is acceptablefor some applications. The chassis 10 also includes a manual parkingbrake interface 162 that may be necessary for certain applications andtherefore is also optionally used with other embodiments.

[0106]FIG. 18 depicts an embodiment of the invention that may beadvantageous in some circumstances. The energy conversion system 67includes an internal combustion engine 167 with horizontally-opposedcylinders, and a transmission 169. The energy storage system 69 includesa gasoline tank 171.

[0107]FIG. 19 depicts an embodiment of the invention wherein thesteering system 81 has mechanical control linkages including a steeringcolumn 173. Passenger seating attachment couplings 175 are present onthe body attachment interface 87, allowing the attachment of passengerseating assemblies to the chassis 10.

[0108]FIGS. 20 and 20a depict a chassis 10 within the scope of theinvention and a body 85 each having multiple electrical connectors 91and multiple complementary electrical connectors 95, respectively. Forexample, a first electrical connector 91 may be operably connected tothe steering system and function as a control signal receiver. A secondelectrical connector 91 may be operably connected to the braking systemand function as a control signal receiver. A third electrical connector91 may be operably connected to the energy conversion system andfunction as a control signal receiver. A fourth electrical connector 91may be operably connected to the energy conversion system and functionas an electrical power connector. Four multiple wire in-line connectorsand complementary connectors are used in the embodiment shown in FIGS.20 and 20 a. FIG. 20a depicts an assembly process for attachingcorresponding connectors 91, 95.

[0109] Referring to FIG. 21, a further embodiment of the claimedinvention is depicted. The chassis 10 has a rigid covering 161 and aplurality of passenger seating attachment couplings 175. Adriver-operable control input device 177 containing a steeringtransducer, a braking transducer, and an energy conversion systemtransducer, is operably connected to the steering system, brakingsystem, and energy conversion system by wires 179 and movable todifferent attachment points.

[0110] The embodiment depicted in FIG. 21 enables bodies of varyingdesigns and configurations to mate with a common chassis design. Avehicle body without a lower surface but having complementary attachmentcouplings is matable to the chassis 10 at the load-bearing bodyretention couplings 89. Passenger seating assemblies may be attached atpassenger seating attachment couplings 175.

[0111] Referring to FIG. 22, a rigid aluminum sheet (a.k.a. belly pan orstructural sheet member) 180 is schematically depicted. The rigid sheethas a plurality of formations 183 that define a plurality of cavities186 and is formed from a single sheet of metal. In the embodiment shown,the formations include integrated structural members such as rails 187and cross members 188. The rigid sheet 180 also includes attachmentelements 192 which are holes formed in the rigid sheet in the embodimentshown. The rigid sheet 180 enables a simplified manufacturing processwherein chassis components are placed into the preformed cavities 186and are attached at the attachment elements 192. Preferably, the size,shape and location of the cavities 186 are predetermined to locate andat least partially contain chassis components. The rigid sheet 180 maybe used in conjunction with the structural frame or, as in theembodiment shown in FIG. 22, may include structural features such thatit functions as a structural frame.

[0112] An enabling technology for manufacturing the above describedrigid sheet is the so-called “quick plastic forming” technology, asdescribed in U.S. Pat. No. 6,253,588, which is assigned to GeneralMotors Corp., and is hereby incorporated by reference. Using quickplastic forming, a large AA 5083 type aluminum-magnesium alloy sheetstock may be formed into a complex three-dimensional shape with highelongation regions, at high production rates. The magnesium containingaluminum sheet is heated to a forming temperature in the range of about400° C. to 510° C. (750° F. to 950° F.). The heated sheet is stretchedagainst a forming tool and into conformance with the forming surface ofthe tool by air or gas pressure against the back surface of the sheet.The gas pressure is preferably increased continuously or step-wise from0 p.s.i. gauge at initial pressurization to a final pressure of about250-500 p.s.i. (gauge pressure, i.e. above ambient pressure) or higher.During the first several seconds of the process up to about 1 minute ofincreasing pressure application, the sheet accommodates itself on thetool surface. After this initial period of pressurization to initiatestretching of the sheet, the pressure can then be increased at an evenfaster rate. Depending upon the size and complexity of the panel to beformed, such forming can normally be completed in a period of about 2-12minutes.

[0113] Alternatively, super plastic forming (SPF) may be used tomanufacture the rigid sheet, as described in U.S. Pat. No. 5,974,847,which is assigned to General Motors Corp., and is hereby incorporated byreference. The SPF method is used for stretch forming a flat ductilealuminum alloy sheet to reduce metal thinning and tears in the formedproduct. The method includes placing the sheet between first and seconddie members movable between a die open position, for insertion of thesheet and removal of a formed product, and a die closed position inwhich the dies sealingly engage the periphery of the sheet for stretchforming of the die enclosed area of the sheet utilizing differential gaspressure. The first die member has a forming surface and defines acavity between the forming surface and a first surface of the sheet, andthe second die member has a sheet metal shaping surface opposite thecavity. The dies are first in the die open position and the sheet ispositioned between the preform surface and the cavity. The sheet is thenheated to a stretch forming temperature. Thereafter, the dies are movedto their closed position such that the first die engages the peripheryof the sheet and pulls the heated sheet against the second die shapingsurface to draw sheet material into the cavity so that the sheet is nolonger flat and more sheet material is disposed within its sealinglyengaged periphery than if the sheet had remained flat. Gas pressure isthen applied to the second side of the sheet to stretch the sheet intoconformity with the first die forming surface.

[0114] Referring to FIG. 23, wherein like reference numbers refer tolike components from FIG. 22, a chassis assembly scenario 189 employingthe rigid sheet 180 is schematically depicted. In a first assembly step191, a fuel cell stack 125 is assembled at least partially within acavity 186 and mounted to the rigid sheet 180 at the attachment elements192. The cavity 186 into which the fuel cell stack 125 is placed is of apredetermined size sufficient to partially contain the fuel cell stack125 and to positively locate it relative to the rigid sheet 180 andother chassis components.

[0115] In a second assembly step 195, two cylindrical compressed gasstorage tanks 121 forming the energy storage system of the chassis arepositioned in a second cavity 186 and attached to the rigid sheet 180 atattachment elements 192. The cavity 186 into which the tanks 121 areplaced are of a predetermined size, shape and location to at leastpartially contain the storage tanks 121 and to positively locate themwith respect to the rigid sheet 180 and other chassis components such asthe fuel cell stack 125.

[0116] In a third assembly step 198, an electric motor 127 (a componentof the energy conversion system), a load bearing body retention coupling89, and an auxiliary energy conversion system unit 201 are each placedin respective cavities 186, wherein each of the cavities is of apredetermined size, shape and location so as to accommodate and at leastpartially contain the component placed therein, and to positively locateeach of the components 127, 89, 201 with respect to the other componentssuch as the fuel cell stack 125 and the fuel tanks 121, and with respectto the rigid sheet 180.

[0117] A further aspect of the invention is shown in FIG. 24, in whichan engineered body floorpan 204 is schematically depicted. Theengineered body floorpan 204 is a structural base or platform from whichvariations in vehicle body packaging design and engineering can befacilitated. The engineered floorpan 204 enables the attachment of bodystructures and hardware. The engineered floorpan 204 is engineered forattachment to a rolling platform (i.e. chassis) and includescomplementary connection components, such as complementary attachmentcouplings 93 and a complementary electrical connector 95. Thesecomponents can be seen on the top surface of the body floorpan 204 inFIG. 24 because they protrude through the body floorpan for engagementwith a chassis under the floorpan. Body hardware and structures may bemounted at attachment points 207, which are illustrated in FIG. 24 asholes formed in the engineered floorpan 204. The engineered floorpan 204includes formations 208 to provide structural rigidity to the floorpan204 and, optionally, wheel wells 210. Again, enabling technologies formanufacturing the body floorpan are the above-described quick plasticforming and super plastic forming technologies.

[0118] Referring to FIG. 20a, a body assembly scenario advantageouslyemploying an engineered floorpan 204 is schematically depicted whereinlike reference numbers refer to like components from FIG. 24. In a firstbody assembly step 216, a driver-operable control input device 177 ismounted to the engineered floorpan 204 via attachment elements 207 in apredetermined location. Although not all attachment elements 207 areidentified with reference numbers in the Figures, they are spread acrossthe floorpan to facilitate attachment of numerous body components. In asecond body assembly step 219, passenger seating apparatuses 220 areattached to the engineered floorpan 204 via attachment elements 207 in apredetermined location. In a third body assembly step 222, bodystructures 223 including the roof, doors, close-outs, etc. are mountedto the engineered floorpan 204 via attachment elements 207 to form avehicle body 85.

[0119] Referring to FIG. 25, wherein like reference numbers refer tolike components from FIGS. 1-4 and 22-24, an attachment scenario betweena vehicle body 85 having an engineered floorpan 204 and a vehiclechassis 10 including the rigid sheet (belly pan) 180 is schematicallydepicted. The rigid sheet 180 may be positioned and configured such thatit functions as a belly pan as shown in FIG. 25. It may also bepositioned above the various chassis components such that it forms theupper chassis face and functions as a rigid covering 161, as shown inFIGS. 16 and 17.

[0120]FIG. 26 schematically illustrates in frame 1 a rigid sheet 180that is manufactured using quick plastic forming (QPF) as describedpreviously, and is initially provided to serve as an attachmentstructure for the parts, hardware and components of the rolling chassis.Frame 2 shows the addition of wheels 73, 75, 77, 79, traction motor 127and structural elements for a structural frame 11. Frame 3 depicts theaddition of the fuel cell 125 and other hardware and components.Finally, frame 4 shows the addition of closeouts such as a rigidcovering 161, thereby presenting a fully skinned rolling chassis 10.

[0121]FIG. 27 illustrates the assembly of a vehicle body pod 85,starting with an engineered floorpan 204 or stamped structural floor inthe first frame. The floorpan is preferably manufactured using quickplastic forming (QPF). In the second frame, body skeleton components 225as well as seats, large interior hardware and electrical cables areadded. In the third frame, doors, glass and other panels and closures228 are added to complete a body pod 85. In the fourth frame the bodypod 85 is assembled to the rolling chassis 10.

[0122]FIG. 28 is a schematic depiction of a chassis assembly processthat advantageously incorporates a rigid sheet (such as the rigid sheet180 described previously) to provide positive location for chassiscomponents. The method includes providing a rigid sheet havingformations defining a plurality of cavities of a predetermined size,shape, and location to partially contain chassis components, and topositively locate chassis components (step 230). The rigid sheet mayalso include formations that function as integrated rails andcross-members, and may be formed by quick plastic forming or superplastic forming. The method also includes positioning chassis componentswithin the plurality of cavities (step 233), wherein the chassiscomponents include components for an energy conversion system, steeringsystem, and braking system. Other components that may be placed withinthe plurality of cavities include energy storage system components;wheels; suspension system components; heating, ventilating, and airconditioning components; wiring; load-bearing body-retention couplings;and structural elements. The method also includes interconnecting thecomponents and the rigid sheet sufficiently to result in an operablechassis (step 236), and mating the rigid sheet and the components to avehicle body to form a vehicle (step 239). The rigid sheet (belly pan)also enables modular chassis components, such as fuel cells and hydrogenstorage tanks, to be interchanged on the rigid sheet over the life ofthe chassis.

[0123] Referring again to FIG. 5, a method of employing engineeredfloorpans is schematically depicted. Three chassis 10 having bodyconnection components 89, 91 in the same predetermined spatialrelationship are each matable with three different vehicle bodies 85,85′, 85″, each body 85, 85′, 85″ having a different style orconfiguration. Each body 85, 85′, 85″ is built upon a common base 98,consisting of an engineered floorpan substantially as shown anddescribed in FIGS. 24 and 20a.

[0124] As set forth in the claims, various features shown and describedin accordance with the different embodiments of the inventionillustrated may be combined.

[0125] While the best modes for carrying out the invention have beendescribed in detail, those familiar with the art to which this inventionrelates will recognize various alternative designs and embodiments forpracticing the scope of the invention within the scope of the appendedclaims.

1. A vehicle chassis comprising: a rigid sheet having formationsdefining a plurality of cavities; at least three wheels mounted withrespect to the rigid sheet; an energy conversion system operablyconnected to at least one wheel; an energy storage system operablyconnected to the energy conversion system; a steering system operablyconnected to at least one wheel; and a braking system operably connectedto at least one wheel; wherein the energy conversion system and energystorage system are mounted to the rigid sheet and at least partiallylocated within one of the plurality of cavities.
 2. The vehicle chassisof claim 1, wherein the rigid sheet includes a plurality of attachmentcouplings, and wherein each of the energy conversion system, energystorage system, steering system, and braking system is mounted to therigid sheet at at least one of the plurality of attachment couplings. 3.The vehicle chassis of claim 2, wherein the plurality of attachmentcouplings are holes configured to engage a fastening element.
 4. Thevehicle chassis of claim 2, wherein the rigid sheet is positioned andconfigured to function as a belly pan.
 5. The vehicle chassis of claim4, wherein the rigid sheet is positioned and configured such that itforms an upper chassis face.
 6. The vehicle chassis of claim 5, furthercomprising a body attachment interface having body connectioncomponents, the body connection components including at least oneload-bearing body-retention coupling mounted with respect to the rigidsheet and exposed at or above the upper chassis face.
 7. The vehiclechassis of claim 6, wherein the body connection components furtherinclude at least one electrical connector mounted with respect to therigid sheet and exposed at or above the upper chassis face.
 8. Thevehicle chassis of claim 1, wherein the rigid sheet is characterized byformations configured to provide structural integrity.
 9. The vehiclechassis of claim 8, wherein the formations include integrated rails andcross-members.
 10. The vehicle chassis of claim 1, wherein the energyconversion system includes a fuel cell stack.
 11. The vehicle chassis ofclaim 10, wherein the energy conversion system includes an electricmotor.
 12. The vehicle chassis of claim 1, wherein the rigid sheet ismanufactured by quick plastic forming (QPF).
 13. The vehicle chassis ofclaim 1, wherein the system and braking system are mounted to the rigidsheet and at least partially located within the cavities.
 14. A methodof assembling a vehicle chassis, comprising: mounting an energyconversion system, energy storage system, steering system, and brakingsystem to a rigid sheet; wherein the energy conversion system, energystorage system, steering system, and braking system are each comprisedof a plurality of operably interconnected components; wherein the rigidsheet is formed to include a plurality of cavities of predeterminedsize, location, and shape; wherein the predetermined size, location, andshape of each of the plurality of cavities is determined to position atleast one of the components with respect to the rigid sheet and to atleast partially contain the at least one interconnected component in thecavities.
 15. The method of claim 14, wherein at least one component ofeach system is at least partially positioned within one of saidcavities.
 16. The method of claim 14, further comprising positioninghydrogen storage tanks and a fuel cell in said cavities.
 17. The methodof claim 14, further comprising positioning an electric motor in one ofsaid cavities.
 18. The method of claim 14, further comprisingpositioning a load-bearing body-retention coupling in one of saidcavities.
 19. The method of claim 14, further comprising manufacturingthe rigid sheet using quick plastic forming (QPF).
 20. The method ofclaim 14, further comprising mating the rigid sheet to a body to form avehicle.
 21. A vehicle chassis comprising: a one-piece structural sheetmember formed from a single sheet of metal, and defining a plurality ofcavities; a suspension system including at least three wheels mountedwith respect to the structural sheet member; a steering system havingsteering components, mounted with respect to the structural sheet memberand operably connected to at least one wheel; a propulsion system havingpropulsion system components, mounted with respect to the structuralsheet member and operably connected to at least one wheel; a brakingsystem having braking components, mounted with respect to the structuralsheet member and operably connected to at least one wheel; a pluralityof body attachment couplings mounted with respect to the structuralmember, including a plurality of body retention couplings and a controlsignal receiver coupling; wherein the steering components, propulsionsystem components and braking components are mounted at least partiallywithin the cavities.
 22. The vehicle chassis of claim 21, wherein theone-piece structural sheet member includes integrated rails and crossmembers.
 23. The vehicle chassis of claim 21, wherein the one-piecestructural sheet member is formed from a single sheet of aluminum alloy.24. The vehicle chassis of claim 21, wherein the one-piece structuralsheet member is formed using quick plastic forming.
 25. The vehiclechassis of claim 21, wherein the propulsion system includes a fuel cell.